- Procalcitonin is a precursor for calcitonin, the production of which is upregulated in response to inflammatory states.
- Unlike other inflammatory markers, procalcitonin elevation is somewhat specific to certain bacterial antigens.
- Conversely, viral infections typically result in the production of interferon gamma, which decreases the production of procalcitonin. Therefore, theoretically, procalcitonin might be helpful as an inflammatory marker that could distinguish between viral and bacterial illnesses.
- Studies have investigated numerous uses of procalcitonin, including whether the test can differentiate between viral and bacterial infections, whether trending procalcitonin levels can guide antibiotic duration, and whether it can be used to rule in or rule out an infectious process.
- In the ED, the major hope for procalcitonin is that we can apply it to an undifferentiated group of patients with infectious symptoms and determine who has a bacterial infection where we can intervene to improve the outcome.
- Respiratory Infections
- Accuracy for distinguishing bacterial pneumonia (Kamat 2020).
- Sensitivity of 55%
- Specificity of 76%
- “A procalcitonin level is unlikely to provide reliable evidence either to mandate administration of antibiotics or to enable withholding such treatment in patients with CAP.”
- Procalcitonin performed worse than clinical judgment (Maisal 2012).
- ProACT Study (Huang 2018): No difference in antibiotic prescribing between a procalcitonin-driven algorithm and usual care.
- An outpatient study (Briel 2008) showed that the procalcitonin protocol could decrease antibiotic use. However, the overall antibiotic prescribing rate was extremely high at baseline in the study group and antibiotic use wasn’t decreased because patients were given delayed prescriptions (not no prescription).
- Accuracy (Wacker 2013):
- Sensitivity 77%
- Specificity 79%
- Not high enough to rule in or rule out sepsis.
- HiTEMP Trial (van der Does 2018):
- No change in antibiotic use or other clinically meaningful outcomes
- Pediatric Fever
- Accuracy in determining whether neonate with fever has a dangerous bacterial infection (Millicent 2016):
- Sensitivity 74%
- Specificity 78%
- PECARN and Step-by-Step tools use procalcitonin in decision-making. However, due to the way the studies were designed, it’s unclear if procalcitonin is adding value in the rules.
- Stopping antibiotics
- A number of randomized controlled trials show that procalcitonin can safely aid clinicians in stopping or shortening courses of antibiotics in the ICU.
- It is unclear whether a procalcitonin-driven algorithm is better than clinical judgment.
- To determine the utility of procalcitonin, we need studies that compare the use of procalcitonin with standard practice (ie, clinical judgment).
First 10 EM: https://first10em.com/procalcitonin-in-the-ed-the-evidence/
Procalcitonin to distinguish viral From bacterial pneumonia: a systematic review and meta-analysis
Kamat IS, Ramachandran V, Eswaran H, et al. Clin Infect Dis. 2020;16;70(3):538-542. doi: 10.1093/cid/ciz545. PMID: 31241140
Procalcitonin-guided use of antibiotics for lower respiratory tract infection
Huang DT, Yealy DM, Filbin MR, et al; ProACT Investigators. N Engl J Med. 2018;19;379(3):236-249. doi: 10.1056/NEJMoa1802670. PMID: 29781385
Use of procalcitonin for the diagnosis of pneumonia in patients presenting with a chief complaint of dyspnoea: results from the BACH (Biomarkers in Acute Heart Failure) trial
Maisel A, Neath SX, Landsberg J, et al. Eur J Heart Fail. 2012;14(3):278-286. doi: 10.1093/eurjhf/hfr177. PMID: 22302662
Procalcitonin-guided antibiotic use vs a standard approach for acute respiratory tract infections in primary care
Briel M, Schuetz P, Mueller B, et al. Arch Intern Med. 2008;168(18):2000-2007; discussion 2007-2008. doi: 10.1001/archinte.168.18.2000. PMID: 18852401
Procalcitonin as a diagnostic marker for sepsis: a systematic review and meta-analysis
Wacker C, Prkno A, Brunkhorst FM, et al. Lancet Infect Dis. 2013;13(5):426-435. doi: 10.1016/S1473-3099(12)70323-7. PMID: 23375419
Procalcitonin-guided antibiotic therapy in patients with fever in a general emergency department population: a multicentre non-inferiority randomized clinical trial (HiTEMP study)
van der Does Y, Limper M, Jie KE, et al. Clin Microbiol Infect. 2018;24(12):1282-1289. doi: 10.1016/j.cmi.2018.05.011. PMID: 29870855
Use of procalcitonin assays to predict serious bacterial infection in young febrile infants.
Milcent K, Faesch S, Gras-Le Guen C, et al. JAMA Pediatr. 2016;170(1):62-69. doi: 10.1001/jamapediatrics.2015.3210. Erratum in: JAMA Pediatr. 2016;170(6):624. PMID: 26595253